Dringenberg H C, Kornelsen R A, Pacelli R, Petersen K, Vanderwolf C H
University of Western Ontario, London, Canada.
Behav Brain Res. 1998 Nov;96(1-2):161-72. doi: 10.1016/s0166-4328(98)00010-2.
Unlesioned rats exploring a black-white two compartment box spent most of the time in the covered, black half of the box and only little time in the uncovered, white half (67 s/5 min). Large radio-frequency lesions of the amygdala or hippocampus did not alter this pattern of exploration, but rats with hippocampus lesions were more active than the other two groups of rats. Treatment with the 5-HT1A receptor agonist buspirone (0.1 mg/kg, s.c.) increased the time that unlesioned rats spent in the uncovered compartment (103 s), an effect that was less pronounced in hippocampus-lesioned rats and completely abolished by amygdala lesions. In a food transport test, unlesioned rats that traveled from a home cage to an exposed food source consumed small and medium-sized pellets immediately at the food source. Larger pellets, however, were carried back to the home cage for consumption. Rats with amygdala lesions ate fewer pellets at the food source and tended to carry more pellets back to the home cage for consumption than unlesioned rats. Rats with hippocampus lesions carried fewer pellets back to the home cage and ate more pellets at the food source. Buspirone (0.5-1.5 mg/kg, s.c.) reduced the carrying of large food items to the home cage and increased consumption of these pellets at the food source in all groups of rats. These results suggest that neither the amygdala nor the hippocampus play an important role in controlling exploratory behavior in a black-white compartment box, but that the amygdala may have some role in mediating the effect of buspirone to increase exploration of the white/open compartment. Further, the amygdala and hippocampus have opposing influences on the transport of food items to a shelter, the amygdala suppressing food carrying, and the hippocampus enhancing it. Neither structure is essential for the effect of buspirone to reduce food carrying. The hypothesis that limbic structures mediate 'fear/anxiety' responses is discussed critically.
未受损的大鼠在探索黑白两室箱时，大部分时间都待在有盖的黑色区域，而在无盖的白色区域停留时间很少（5分钟内67秒）。杏仁核或海马体的大面积射频损伤并未改变这种探索模式，但海马体受损的大鼠比其他两组大鼠更活跃。用5-羟色胺1A受体激动剂丁螺环酮（0.1毫克/千克，皮下注射）处理后，未受损大鼠在无盖区域停留的时间增加（103秒），这种效应在海马体受损的大鼠中不太明显，而在杏仁核受损的大鼠中则完全消失。在食物搬运测试中，从未受损的家笼移动到暴露食物源的大鼠会在食物源立即吃掉中小颗粒的食物。然而，较大颗粒的食物会被带回笼子里食用。杏仁核受损的大鼠在食物源吃掉的颗粒较少，并且比起未受损的大鼠，它们倾向于带回更多颗粒到笼子里食用。海马体受损的大鼠带回笼子的颗粒较少，而在食物源吃掉的颗粒较多。丁螺环酮（0.5 - 1.5毫克/千克，皮下注射）减少了所有组大鼠将大食物带回笼子的行为，并增加了它们在食物源对这些颗粒的消耗。这些结果表明，杏仁核和海马体在控制黑白两室箱中的探索行为方面都不发挥重要作用，但杏仁核可能在介导丁螺环酮增加对白色/开放区域探索的效应中发挥一定作用。此外，杏仁核和海马体对将食物搬运到庇护所的行为有相反的影响，杏仁核抑制食物搬运，而海马体则增强这种行为。对于丁螺环酮减少食物搬运的效应，这两个结构都不是必需的。文中对边缘系统结构介导“恐惧/焦虑”反应的假说进行了批判性讨论。
